Views: 0 Author: Amelie Publish Time: 2026-09-21 Origin: Site
Small ceramic components are easy to overlook in semiconductor equipment.
A ceramic spacer may only be a few millimeters across. A thin insulating plate may look like a simple washer or shim. But when the part has to maintain a precise gap, provide electrical insulation, transfer heat, and remain stable at elevated temperatures, material selection becomes much more important.
Aluminum nitride (AlN) is one of the ceramic materials used for these applications because it combines relatively high thermal conductivity with electrical insulation, low thermal expansion, and good high-temperature performance.
Large AlN components such as heater plates and electrostatic chucks are well known in semiconductor manufacturing. Less attention is given to the smaller AlN components used around these assemblies, including spacers, shims, washers, insulating plates, supports and other custom ceramic parts.
This article looks at where these small aluminum nitride ceramic parts are used, why AlN is selected, and what engineers should consider when designing or sourcing them.
An aluminum nitride ceramic spacer is a precision ceramic component used to maintain a defined distance between components while providing electrical insulation.
Unlike a conventional metal spacer, an AlN spacer can also conduct heat relatively efficiently.
This combination is useful when an assembly requires both electrical isolation and thermal management.
Depending on the equipment design, an AlN ceramic spacer may be manufactured as:
A thin square or rectangular plate
A small shim
A washer or ring
A plate with mounting holes
A slotted insulating piece
A stepped component
A custom-shaped ceramic part
The dimensions can be surprisingly small.
For example, Valley Design's published AlN spacer and shim range includes square AlN parts from 1 mm to 4 mm and thicknesses from approximately 0.127 mm to 2.5 mm. The company also states that larger and smaller sizes and tighter tolerances are available.
This is a useful indication that small AlN ceramic components are not simply theoretical applications. They are commercially manufactured precision parts.
The reason for choosing aluminum nitride is usually not one property alone.
Engineers may select AlN when several requirements have to be met at the same time.
AlN has much higher thermal conductivity than conventional electrical insulating materials such as many grades of alumina.
The exact value depends on the material grade and manufacturing process.
AlN is electrically insulating while still providing good thermal conduction.
That combination is useful around:
Heater assemblies
Electrodes
RF components
Plasma equipment
Wafer-processing components
Thermal-management structures
This is one reason AlN is used in semiconductor equipment where a metal spacer would not be suitable.
AlN has a relatively low coefficient of thermal expansion, and its thermal expansion behavior is relatively close to silicon.
This can be useful in assemblies exposed to repeated heating and cooling, particularly where dimensional stability is important.
Semiconductor processing equipment can operate at elevated temperatures, so the ceramic component needs to remain stable during operation.
The appropriate AlN grade depends on the temperature, atmosphere, electrical requirements and other process conditions.
Small AlN components can appear in many different parts of semiconductor equipment.
The exact component geometry is normally determined by the equipment manufacturer rather than by the ceramic supplier.
One of the clearest applications of AlN is semiconductor heating.
CoorsTek's semiconductor deposition equipment page identifies AlN as a material used in heater plates for deposition equipment. The company notes that these heaters require uniform thermal distribution, high purity and plasma resistance.
The heater itself may be a large component, but the surrounding assembly can also require smaller ceramic components for insulation, spacing, mounting and thermal management.
This is where small AlN plates and spacers can become relevant.
Electrostatic chucks, or ESCs, are another major AlN application.
The function of an ESC is not simply to hold a wafer. It may also need to control thermal behavior and withstand the process environment.
NGK also publishes AlN material grades with different thermal conductivity, resistivity and mechanical properties.
This illustrates an important point for engineers:
“AlN” is not a complete material specification.
The required AlN grade depends on the application.
Deposition and etching equipment can expose internal components to plasma, elevated temperature and chemically aggressive environments.
CoorsTek's semiconductor deposition information lists chamber components including chamber lids, liners, deposition rings, gas distribution plates, pedestal heaters and plating insulators. It identifies high-purity alumina and AlN among the ceramic materials used for these equipment challenges.
For smaller components, the required function may be much simpler:
Maintain a defined spacing
Electrically isolate two components
Provide thermal conduction
Support a component
Maintain alignment
Reduce metal-to-metal contact
A small AlN spacer may therefore be part of a much larger equipment assembly.
AlN is not automatically the right choice for every application.
Alumina remains one of the most widely used technical ceramics because it offers good electrical insulation, high-temperature performance and relatively economical manufacturing.
The decision often comes down to what the component needs to do.
Requirement | AlN | Alumina |
|---|---|---|
Thermal conductivity | High | Lower than AlN |
Electrical insulation | Excellent | Excellent |
Thermal management | Excellent | Good |
High-temperature performance | Excellent | Excellent |
Thermal expansion matching to silicon | Advantage | Less closely matched |
Material cost | Generally higher | Generally lower |
Machining cost | Generally higher | Generally lower |
If a component is mainly required to provide electrical insulation and mechanical support, alumina may be sufficient.
If the component also needs to transfer heat efficiently, AlN may be a better technical fit.
The correct choice should therefore be based on the complete application rather than simply choosing the more expensive ceramic.
A small AlN component can look simple on a drawing, but several details can affect manufacturing.
The drawing may specify:
AlN purity
Thermal conductivity
Density
Volume resistivity
Dielectric strength
Thermal expansion coefficient
Different grades can have substantially different properties.
Thickness becomes especially important for small plates and shims.
A very thin ceramic component can require additional control of:
Thickness
Flatness
Warpage
Edge condition
Handling damage
The thinner the part becomes, the more important the manufacturing process becomes.
Small AlN components may contain:
Through holes
Blind holes
Mounting holes
Locating holes
Slots
Cut-outs
Hole diameter, hole depth and the distance between a hole and the edge should be considered together.
Very small holes in brittle ceramic materials can create machining and edge-chipping challenges.
If the AlN spacer sits between two precision components, excessive flatness or parallelism error can affect the final assembly.
For this reason, a drawing may specify:
Flatness
Parallelism
Thickness tolerance
Surface roughness
These requirements should be discussed before production rather than added after machining.
The required surface finish depends on how the ceramic part contacts other components.
Possible processes include:
Precision grinding
Lapping
Polishing
Valley Design, for example, publishes lapped and polished surface options for precision AlN spacers and shims.
One reason is that AlN is not a conventional engineering plastic or metal.
It is a hard, brittle technical ceramic, and the manufacturing process has to account for the material's behavior during forming, sintering and machining.
For small parts, common manufacturing concerns include:
Small holes, slots and sharp corners can be vulnerable to chipping during machining.
Thin plates require careful control of the manufacturing and finishing processes.
Sintering introduces dimensional changes, so the final machining allowance must be considered during process planning.
The required surface finish may require grinding, lapping or polishing rather than simply conventional CNC machining.
Thin and small ceramic parts can be damaged during handling, cleaning and inspection.
This is why a drawing review before production is particularly useful for small AlN components.
There is no single standard shape for an AlN spacer.
A semiconductor equipment drawing might specify something as simple as:
20 × 15 × 1 mm rectangular plate
or a more complicated geometry with several holes, slots and steps.
Other examples include:
10 × 10 × 0.5 mm AlN shim
Small square insulating plate
AlN washer with precision inner diameter
AlN ring
AlN plate with multiple mounting holes
Stepped AlN support
Custom AlN thermal spacer
These dimensions are examples only. The actual size and tolerance should be determined from the equipment design.
For reference, commercially published AlN precision spacer sizes can be much smaller. Valley Design lists AlN square spacers from 1 mm upward and thicknesses from approximately 0.127 mm upward.
At Hero Ceramic, we manufacture custom technical ceramic components according to customer drawings and samples.
Our ceramic materials include:
Aluminum Nitride (AlN)
Alumina (Al₂O₃)
Silicon Carbide (SiC)
Silicon Nitride (Si₃N₄)
Zirconia (ZrO₂)
For small AlN components, the manufacturing process can include precision grinding, CNC machining, hole machining, surface finishing and dimensional inspection according to the requirements of the drawing.
Typical custom components include:
AlN spacers
AlN shims
Insulating plates
Washers
Rings
Supports
Small precision ceramic parts
For a new project, we recommend reviewing the drawing before production, particularly when the part has thin sections, small holes, tight tolerances or demanding flatness requirements.
Have a small AlN ceramic part that is difficult to source? Send us your drawing or sample for a manufacturing review and quotation.
An AlN ceramic spacer is used where controlled spacing and electrical insulation are required, particularly when the ceramic also needs to provide relatively efficient heat transfer.
AlN combines high thermal conductivity, electrical insulation, relatively low thermal expansion and high-temperature performance. These properties make it suitable for applications such as semiconductor heaters, electrostatic chucks and other thermal or insulating components.
The main difference is thermal conductivity. AlN generally provides much higher thermal conductivity, while alumina is often selected when electrical insulation and cost are the primary considerations.
Yes. AlN can be precision ground and machined using processes suitable for technical ceramics. The achievable tolerance depends on the material grade, geometry, thickness, holes and surface requirements.
Yes. Small AlN spacers, shims, plates, washers and other custom geometries can be manufactured according to customer drawings or samples.
A 2D drawing with material, dimensions, tolerances, surface finish and quantity is ideal. If the material specification is not finalized, the operating temperature and thermal/electrical requirements are also useful.
Aluminum nitride is already an established material in semiconductor manufacturing equipment. Publicly available information from companies such as CoorsTek and NGK shows its use in heaters and electrostatic chucks, while precision ceramic manufacturers such as Valley Design publicly offer AlN spacers, shims and other small components.
For a small AlN ceramic component, the material itself is only part of the engineering decision.
Thermal conductivity, purity, thickness, flatness, surface finish, hole geometry and dimensional tolerances all need to match the actual application.
For OEM and semiconductor equipment projects, a detailed drawing or sample is usually the best starting point for evaluating manufacturability and selecting the appropriate ceramic material.
